The present invention relates to antenna assemblies for wireless communication devices. The invention is particularly useful for cellular telephone communication devices and is, therefore, described below with respect to this application.
Great concern has been expressed that the magnetic component of the near-field radiation, which penetrates the user's head and causes thermal heating within the brain soft tissues due to induced eddy currents, could have a deleterious effect on the user, particularly over the long term. The electrical component of the near-field radiation, which does not penetrate the user's head due to skin conductivity, does not have such a deleterious effect on the user. Many techniques have been proposed to shield the user's head from the antenna, or for otherwise distancing the user's head from the antenna, since the radiation absorbed varies inversely to an inordinate degree with respect to this distance.
Moreover, the signal strength at which the cellular phone operates, and its antenna radiation pattern in space, not only affect the near-field radiation produced by the cellular phone, but also affect the usable period of the battery supply before recharging or replacement is required.
It would therefore be desirable to provide an antenna assembly which enables the cellular phone to be operated with better communication quality and less power, not only to reduce the near-field radiation produced by the cellular phone, but also to increase the usable period of the battery power supply before requiring recharging or replacement.